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Abstract:

The present invention relates to a device (1) for automatic injection of
a product (3) comprising a container (2), a needle (6) and a piston (7)
and, a housing (12) receiving said container (2), said container (2)
being movable with respect to said housing (12) between an initial
position and an insertion position, distally spaced relative to said
initial position, a safety shield (8) coupled to said housing (12) and
movable with respect thereto between a rest position, an activation
position, proximally spaced relative to said rest position, and a safety
position, distally spaced with respect to said rest position, biasing
means (33) for causing the movement of said safety shield (8) to said
safety position, triggering means (29) for causing the container (2) to
move from its initial position to its insertion position, said triggering
means (29) being releasable by movement of said safety shield (8) to said
activation position, characterized in that said device (1) further
comprises: isolating means (24) for isolating said safety shield (8) from
said biasing means (33) when said safety shield (8) is moved to its
activation position.

Claims:

1. A device (1) for automatic injection of a product (3) into an
injection site (4), the product (3) being carried by a container (2)
having an open proximal end (2a) and a substantially closed distal end
(2b) and carrying a needle (6) to provide an outlet port for the product
(3) from the container, and a piston (7) provided in the container (2)
and movable with respect to the container, the distal movement of the
piston (7) causing the product (3) to be expelled from the container
through the needle, a housing (12) receiving at least partially said
container (2), said container (2) being movable with respect to said
housing (12) between an initial position, in which a tip (6a) of the
needle (6) does not extend beyond a distal end (12b) of said housing
(12), and an insertion position, distally spaced relative to said initial
position, and in which the tip (6a) of the needle (6) extends beyond said
distal end (12b) of said housing (12), a safety shield (8) coupled to
said housing (12) and movable with respect thereto between a rest
position, an activation position, proximally spaced relative to said rest
position, and a safety position, distally spaced with respect to said
rest position, biasing means (33) for causing the movement of said safety
shield (8) to said safety position, triggering means (29) for causing the
container (2) to move from its initial position to its insertion
position, said triggering means (29) being releasable by movement of said
safety shield (8) to said activation position, characterized in that said
device (1) further comprises: isolating means (24) for isolating said
safety shield (8) from said biasing means (33) when said safety shield
(8) is moved to its activation position.

2. A device (1) according to claim 1, characterized in that said
isolating means comprise a first ring (24), receiving said container (2),
said first ring (24) being coupled to said biasing means (33) in the
proximal direction and coupled to said housing (12) in the distal
direction, and being independent from said safety shield (8), at least
when said safety shield (8) is moved to its activation position.

3. A device (1) according to claim 2, characterized in that said first
ring (24) comprises at least a flexible tooth (26) provided with a distal
abutment surface (26a) and said housing (12) comprises at least a radial
stop (14), said first ring (24) being coupled to said housing (12) in the
distal direction by means of said distal abutment surface (26a) resting
on said radial stop (14), when said safety shield (8) is moved to its
activation position.

4. A device (1) according to claim 3, characterized in that said device
(1) further comprises a second ring (25), said second ring (25) being
fixed to the proximal region of said container (2) and being proximally
spaced with respect to said first ring (24) when said safety shield (8)
is moved to its activation position, said biasing means comprising a
helical spring (33), a proximal end of said helical spring (33) bearing
on a part of said second ring (25) and a distal end of said helical
spring (33) bearing on a part of said first ring (24).

5. A device (1) according to claim 4, characterized in that said flexible
tooth (26) comprises a sloping surface (26b) and said second ring (25)
comprises a distal sloping surface (27), said distal sloping surface (27)
being capable to come in abutment against said sloping surface (26b) so
as to deflect said flexible tooth (26) and disengage said flexible tooth
(26) from said radial stop (14), thereby freeing said first ring (24)
from said housing (12) when said container (12) is in its insertion
position.

6. A device (1) according to claim 5, characterized in that said safety
shield (8) comprises at least one radial rim (9), said radial rim (9)
being located in regards to the distal face (24b) of said first ring
(24), said distal face (24b) of said first ring (24) coming in abutment
against said radial rim (9) when said container (2) is in its insertion
position, thereby coupling said first ring (24) to said safety shield (8)
in the distal direction under the biasing force of the biasing means
(33).

Description:

[0001] The present invention relates to a device for automatic injection
of a product, especially for self-injection, so that the use of the
device is as atraumatic as possible for the patient.

[0002] In this application, the distal end of a component or of a device
is to be understood as meaning the end furthest from the user's hand and
the proximal end is to be understood as meaning the end closest to the
user's hand. Likewise, in this application, the "distal direction" is to
be understood as meaning the direction of injection, and the "proximal
direction" is to be understood as meaning the opposite direction to the
direction of injection.

[0003] Some illnesses necessitate regular injections of drugs or products,
for instance on a daily basis. In order to simplify the treatment, some
self-injectors have been provided in order to allow the patient to
perform the injection on its own.

[0004] Of course, since the patient is usually neither a nurse nor an
educated person in medical devices, such self-injectors must prove to be
very simple to use and also very safe. In particular, the insertion of
the needle must be performed at the right depth, the correct dose of
product must be injected, that is to say a complete injection must be
performed, and the injector must be deactivated after use before it is
disposed of Preferably, the needle should not be exposed, before and
after use, in order to prevent any accidental needlestick injury.
Usually, such self-injectors are provided with a safety shield in order
to protect the needle before use and after use.

[0005] Another important requirement of these self-injection devices is
that they must not be able to be activated inadvertently, before the
patient is ready to perform the injection, and in particular before the
device is correctly applied at the right injection site.

[0006] Such self-injectors with automatic insertion and injection steps,
and a safety shield in order to protect the needle after use have been
described in document WO2007/132353. This document describes a device for
automatic injection in which the injection cannot be triggered before the
device is correctly in place. In particular, the user needs to push
distally on an external housing of the device, once the device is applied
on the injection site, in order to be allowed to trigger the injection.
Nevertheless, in order to complete this step, the user has to overcome
the force of biasing means intended to cause the automatic extension of
the safety shield after use. The force of these biasing means is usually
high and the consequence is that the user may be hurt or may feel a bad
sensation on the skin when accomplishing the step of pushing distally on
the external housing of the device for placing the device correctly and
being allowed to trigger the injection. This bad feeling may refrain the
user/patient from carrying on the administration of the product.

[0007] There is therefore a need for an automatic injection device that
would be safe but at the same time would allow the user/patient to put
the device correctly in place without feeling badly or feeling too high a
pressure on the skin at the injection site.

[0008] The present invention meets this need by proposing a device for
automatic injection of a product into an injection site, said device
comprising a safety system for preventing the triggering of the injection
when the device is not correctly placed on the site of injection, a
safety shield capable of being deployed automatically at the end of
injection under the effect of biasing means, and means for cancelling the
force of said biasing means felt by the patient when said user/patient
completes the step of deactivating the safety system.

[0009] The present invention relates to a device for automatic injection
of a product into an injection site, the product being carried by a
container having an open proximal end and a substantially closed distal
end and carrying a needle to provide an outlet port for the product from
the container, and a piston provided in the container and movable with
respect to the container, the movement of the piston causing the product
to be expelled from the container through the needle, [0010] a housing
receiving at least partially said container, said container being movable
with respect to said housing between an initial position, in which a tip
of the needle does not extend beyond a distal end of said housing, and an
insertion position, distally spaced relative to said initial position,
and in which the tip of the needle extends beyond said distal end of said
housing, [0011] a safety shield coupled to said housing and movable with
respect thereto between a rest position, an activation position,
proximally spaced relative to said rest position, and a safety position,
distally spaced with respect to said rest position, [0012] biasing means
for causing the movement of said safety shield to said safety position,
[0013] triggering means for causing the container to move from its
initial position to its insertion position, said triggering means being
releasable by movement of said safety shield to said activation position,

[0014] characterized in that said device further comprises:

[0015] isolating means for isolating said safety shield from said biasing
means when said safety shield is moved to its activation position.

[0016] The device of the invention provides for a very safe device, which
cannot be triggered as long as it is not correctly located at the
injection site and which does not hurt the user during the step of
deactivating the safety system, said safety system being formed by the
fact that the triggering means cannot be activated as long as the safety
shield has not moved from its rest position to its activation position.
Moreover, in the device of the invention, the needle is automatically
protected after use thanks to biasing means deploying the safety shield.
In particular, because of the presence of specific isolating means in the
device of the invention, the patient does not feel the force of the
biasing means during the step of moving the safety shield from its rest
position to its activation position.

[0017] In an embodiment of the invention, said isolating means comprise a
first ring, receiving said container, said first ring being coupled to
said biasing means in the proximal direction and coupled to said housing
in the distal direction, and being independent from said safety shield,
at least when said safety shield is moved to its activation position.

[0018] In the present application, by the expression "A is coupled to B in
the X direction", one means that A is linked to B when A is moved in the
X direction: in other words, when A is coupled to B in the X direction,
then if A is caused to move in the X direction, then B is also caused to
move in the X direction.

[0019] In the present application, by the expression "A is free or
independent from B", one means that A is not coupled to B.

[0020] In an embodiment of the invention, said first ring comprises at
least a flexible tooth provided with a distal abutment surface and said
housing comprises at least a radial stop, said first ring being coupled
to said housing in the distal direction by means of said distal abutment
surface resting on said radial stop, when said safety shield is moved to
its activation position.

[0021] In an embodiment of the invention, said device further comprises a
second ring, said second ring being fixed to the proximal region of said
container and being proximally spaced with respect to said first ring
when said safety shield is moved to its activation position, said biasing
means comprising a helical spring, a proximal end of said helical spring
bearing on a part of said second ring and a distal end of said helical
spring bearing on a part of said first ring.

[0022] In an embodiment of the invention, said flexible tooth comprises a
proximal sloping surface and said second ring comprises a distal sloping
surface, said distal sloping surface being capable to come in abutment
against said proximal sloping surface so as to deflect said flexible
tooth and disengage said flexible tooth from said radial stop, thereby
freeing said first ring from said housing when said container is in its
insertion position.

[0023] In an embodiment of the invention, said safety shield comprises at
least one radial rim, said radial rim being located in regards to the
distal face of said first ring, said distal face of said first ring
coming in abutment against said radial rim when said container is in its
insertion position, thereby coupling said first ring to said safety
shield in the distal direction under the biasing force of the biasing
means.

[0024] The device of the invention will now be further described in
reference to the following description and attached drawings in which:

[0025] FIG. 1 is a longitudinal cross section view of an embodiment of the
device of the invention before use,

[0026] FIG. 2 is a longitudinal cross section view of the device of FIG.
1, after deactivation of the safety system,

[0027] FIG. 3 is a longitudinal cross section view of the device of FIG. 1
at the time of activation of the triggering means,

[0028] FIG. 4 is a longitudinal cross section view of the device of FIG. 1
once the container is in its insertion position,

[0029] FIG. 5 is a longitudinal cross section view of the device of FIG. 1
at the end of injection.

[0030] Referring now to the drawings, the present invention will now be
described in detail. FIG. 1 shows a longitudinal cross section view of a
device for automatic injection according to an embodiment of the present
invention and generally designated by reference number 1. The device 1 of
the invention comprises a container 2 carrying a product 3 to be injected
into an injection site 4 (see FIGS. 2-5). The container 2 has an open
proximal end 2a provided with a flange 5 and a substantially closed
distal end 2b bearing an injection needle 6. Lateral walls 2c of the
container 2 extend between the proximal and distal ends (2a, 2b) and
define a reservoir 2d sized and shaped to contain a predetermined amount
of a product 3 for injection. The injection needle 6 may be fixed to the
distal end 2b of the container 2, or removable therefrom, as a matter of
design choice. The injection needle 6 is in fluid communication with the
reservoir 2d and provides an outlet port for the product 3 from the
container 2. A piston 7 is provided in the container and movable with
respect to the container 2: as will appear from FIG. 5, the distal
movement of the piston 7 is intended to cause the product 3 to be
expelled from the container 2 through the needle 6. A needle shield (not
represented) may be provided at the distal end 2b of the container 2 to
cover and protect the needle 6 before use of the device 1.

[0031] The device 1 of FIGS. 1-5 further comprises a safety shield 8
receiving at least partially said container 2. On the example shown, the
safety shield 8 has a general tubular shape with an open proximal end 8a
and an open distal end 8b. The proximal end 8a of the safety shield 8 is
provided with at least one radial rim 9 prolonged by a longitudinal leg
10 extending in the proximal direction. The longitudinal leg 10 is
provided with a window 11 separating a proximal portion 10a of said leg
10 from a distal portion 10b of said leg 10.

[0032] The device 1 of FIGS. 1-5 further comprises a housing 12 receiving
at least partially said container 2 and said safety shield 8. On the
example shown, the housing 12 has a general tubular shape with an open
proximal end 12a and an open distal 12b.

[0033] The housing 12 is provided on its internal wall with at least a
flexible leg 13 extending in the proximal direction. The flexible leg 13
is capable of being deflected from a free position in which it extends
radially inwardly (see FIG. 1), to a stressed position in which it
extends longitudinally parallel to the walls of the housing 12 (see FIG.
2).

[0034] The housing 12 further comprises a radial stop 14 located on the
internal wall of said housing 12.

[0035] In its proximal region, the housing 12 is further provided with an
inner cylinder 15 linked to the housing 12 via a radial wall 16. The
inner cylinder 15 has an open proximal end 15a and an open distal end
15b. The cylinder 15 is provided at its proximal end 15a with at least an
inner radial rim 17 and with at least a flexible tooth 18 provided with a
proximal abutment surface 18a.

[0036] The inner cylinder 15 is provided on its outer wall with a flexible
tongue 19 extending in the proximal direction. The flexible tongue 19 is
capable of being deflected from a free position, in which it extends
radially outwardly with respect to the inner cylinder 15 (see FIG. 1) and
a stressed position, in which it extends longitudinally, parallel to the
walls of the inner cylinder 15 (see FIG. 2).

[0037] At its proximal end 12a, the housing 12 is provided on its inner
wall with a radial abutment surface 20.

[0038] As will appear from the following description of FIGS. 1-5, the
container 2 is movable with respect to said housing 12 between an initial
position, in which a tip 6a of the needle 6 does not extend beyond a
distal end 12b of said housing (see FIGS. 1-3) and an insertion position,
distally spaced relative to said initial position, in which the tip 6a of
the needle 6 extends beyond said distal end 8b of said safety shield 8
(see FIG. 4).

[0039] The device 1 of FIGS. 1-5 is further provided with a piston rod 21
intended to push distally the piston 7 in order to expel the product 3
out of the container 2 and realise the injection. On the example shown,
the piston rod 21 is provided at its proximal end with a radial stop 22
and at its distal end with a radial flange 23.

[0040] The device 1 of FIGS. 1-5 further comprises a first ring 24 and a
second ring 25, both rings (24, 25) receiving the container 2. The second
ring 25 is proximally spaced with respect to said first ring 24.

[0041] The first ring 24 has a proximal face 24a and a distal face 24b.
The first ring 24 further comprises a flexible tooth 26, extending in the
proximal direction from the proximal face of said first ring 24, said
flexible tooth 26 being provided with a distal abutment surface 26a and
with a proximal sloping surface 26b. As shown on FIGS. 1 and 2, before
the insertion step, the distal abutment surface 26a of the first ring 24
rests on the radial stop 14 of the housing 12.

[0042] The second ring 25 is fixed to the flange 5 of the container 2 by
classical fixation means (not shown) such as clips, glue, etc. . . . The
second ring 25 has a proximal face 25a and a distal face 25b. The second
ring 25 is further provided with a distal sloping surface 27 and with a
distal skirt 28.

[0043] The device 1 of FIGS. 1-5 further comprises a push button 29
partially received within the distal region of the housing 12. The push
button 29 has the general shape of a tube closed at its proximal end by a
pushing wall 30 and open at its distal end. The pushing wall comprises on
its inner face a peg 31 extending distally. The pushing button 29 is
provided at its distal end with an outer projection 32.

[0044] A first helical spring 33 is provided around the container 2 and
between the first ring 24 and the second ring 25. As shown on FIG. 1, the
proximal end of the first helical spring 33 bears on the distal skirt 28
of the second ring 25 and the distal end of the first helical spring 33
bears on the proximal face 24a of the first ring 24.

[0045] A second helical spring 34 is provided around the piston rod 21. As
shown on FIG. 1, the proximal end of the second helical spring 34 bears
on the inner radial rim 17 of the inner cylinder 15 and the distal end of
the second helical spring 34 bears on the proximal face of the flange 23
of the piston rod 21.

[0046] As will appear from the following description, the safety shield 8
is coupled to said housing 12 and movable with respect thereto between a
rest position, an activation position, proximally spaced relative to said
rest position, and a safety position, distally spaced with respect to
said rest position. As will also appear from the description, the push
button 29 is intended to be used as triggering means for activating the
injection, said triggering means being releasable by movement of said
safety shield 8 to its activation position.

[0047] The functioning of the device 1 will now be explained in reference
to FIGS. 1-5. Before providing a detailed description of the operation of
a device 1 constructed in accordance with the present invention, the
following general description of its operation is provided. The inventive
device 1 is provided to a user ready-to-use. The container 2 is filled
with a predetermined dose of an injectable product 3. At the time of use,
the user places the device 1 against his/her skin at an injection site 4
and applies a distal force on the housing 12. As the housing 12 is
pressed distally, the safety shield 8 is caused to move in the proximal
direction and into the housing 12. Due to a safety system of the
inventive device 1, a user cannot activate the device 1 (i.e., cause the
container 2 to move from its initial position to its insertion position)
until the safety shield 8 is caused to move a predetermined distance in
the proximal direction with respect to the housing 12. Indeed, the
container 2 is in a passive state, ie is not allowed to move from its
initial position to its insertion position, as long as the safety shield
8 has not moved on said predetermined distance. With the device 1 pressed
against his/her skin (and the safety shield 8 moved on said distance in
the proximal direction), the container 2 adopts an active state, and the
user can activate the device 1 and press the push button 29. That will
cause the container 2 to move from its initial position to its insertion
position, which also causes the needle 6 to pierce the user's skin. The
injection may then be realised. Once the injection is complete, the user
removes the device 1 from the injection site and the safety shield 8 is
caused to automatically extend from the housing 12 to cover the
now-contaminated tip 6a of the needle 6. Advantageously, even if the user
removes the device 1 from the injection site 4 before the injection is
complete, the safety shield 8 will automatically extend over the tip of
the needle. Once the device 1 is removed from the injection site 4 and
the shield 8 is extended over the tip of the needle 6, the shield 8 locks
in place and cannot thereafter be moved from its locked position in the
proximal direction to expose the tip 6a of the needle 6. The used device
1 is thus rendered safe for handling and disposal.

[0048] On FIG. 1 is shown the device 1 before use, as provided to the
user. In this position, the flexible leg 13 of the housing is in its free
position and extends radially inwardly: as shown on FIG. 1, said flexible
leg 13 therefore protrudes through the window 11 of the longitudinal leg
10 of the safety shield 8 and engages the distal face 25b of the second
ring 25. The container 2 is by consequence in a passive state: it cannot
move distally. Moreover, in the before use position of FIG. 1, the
flexible tongue 19 of the inner cylinder 15 is also in its free position:
that is to say that said flexible 19 extends radially outwardly with
respect to said cylinder 15. As shown on FIG. 1, in this position, said
flexible tongue 19 faces the distal end of the push button 29. Thus, if
the user pushes on the push button 29, the distal end of the push button
29 abuts on the flexible tongue 19 and the distal movement of the push
button 29 is stopped before the peg 31 reaches the flexible tooth 18 of
the inner cylinder 15. The triggering means, ie the push button 29, is
therefore in a locked position and cannot be released. As shown on FIG.
1, said flexible tooth 18, by its proximal abutment surface 18a being
engaged in the radial stop 22 of the piston rod 21, prohibits any freeing
of the second helical spring 34: the movement of the container 2 to its
insertion position is not possible. In consequence, in the position of
FIG. 1, the injection cannot be activated. The device 1 of the invention
is particularly safe and cannot be activated as long as it is not
correctly placed on the injection site. The flexible tongue 19 and the
flexible leg 13 contribute to the ability of the device 1 to adopt a
locked position and therefore form part of the safety system of the
device of the invention.

[0049] In the position shown on FIG. 1, the first helical spring 33 is in
a partially compressed state and the second helical spring 34 is in a
compressed state. As appears from FIG. 1, the first helical spring 33 is
compressed between the first ring 24 and the second ring 25. Moreover,
the first ring 24 is in abutment on the radial stop 14 of the housing 12
by means of the distal abutment face 26a of said first ring 24 resting on
said radial stop 14. As a consequence, in this before use position as
shown on FIG. 1, the safety shield 8 is not coupled to the first helical
spring 33: in other words, the safety shield 8 is independent and free
from said first helical spring 33. The first ring 24 therefore acts as an
isolating means for isolating or freeing said safety shield 8 from said
first helical spring 33. The safety shield 8 is thus allowed to move with
respect to the housing 12 without interacting with the first helical
spring 33.

[0050] In this position of the device 1, the tip 6a of the needle 6 is
protected by the housing 12 whose distal end 12b extends beyond said tip
6a of the needle 6. In this position of the device 1 also, the safety
shield 8 is in a rest position.

[0051] When the user wishes to proceed with the administration of the
product 3, he applies the device 1 on the skin of the patient at the
injection site 4 and pushes the housing 12 distally, as shown on FIG. 2,
thereby causing the safety shield 8 to move with respect to said housing
12 from its rest position to an activation position, proximally spaced
relative to said rest position. During this step, as explained
hereinabove, the first ring 24 is coupled to the biasing means, ie the
helical spring 33, in the proximal direction and coupled to the housing
12 in the distal direction by means of said distal abutment surface 26a
resting on said radial stop 14, and it is independent or isolated from
said safety shield 8. As a consequence, the safety shield 8 is free or
isolated from the first helical spring 33 and it does not interact with
said first helical spring 33. The patient has therefore no bad feeling on
the skin: the patient does not feel the force of the first helical spring
33. The patient feels better at ease and is not hurt during this step.
This contributes to a safer use of the device 1 for the patient/user.

[0052] As shown on FIG. 2, while the user/patient has pushed distally on
the housing 12, the safety shield 8 has moved proximally with respect to
the housing 12. As a consequence, the distal part 10b of the longitudinal
leg 10 has come in abutment on the flexible leg 13 of the housing 12 and
has put it under stress, forcing it to deflect so as to reach a position
parallel to the wall of the housing 12, as shown on FIG. 2. The flexible
leg 13 of the housing 12 has therefore disengaged from the distal face
25b of the second ring 25. At the same time and as a consequence of the
same movement, the proximal part 10a of the longitudinal leg 10 of the
safety shield 8 has come in abutment on the flexible tongue 19 of the
inner cylinder 15 and has deflected it, forcing it to reach a position
where said flexible tongue 19 is parallel to the wall of the inner
cylinder 15: as shown on FIG. 2, in this position, the flexible tongue 19
no longer faces the distal end of the push button 29.

[0053] The push button 29 is linked to the housing 12 by means of its
outer projection 32 being engaged in the radial abutment surface 20 of
the housing 12; such an engagement allows the push button 29 to move
distally with respect to the housing if a user exerts a distal pressure
on the pushing wall 30 of the push button.

[0054] As appears clearly from FIG. 2, the device 1 and/or the container 2
are now in their active state: the flexible leg 13 is disengaged and the
flexible tongue 19 is also disengaged. The safety shield 8 is now in its
activation position. The triggering means, ie the push button 29, may now
be released and insertion of the container 2 can be triggered.

[0055] In order to trigger the insertion of the container 2, the user
pushes distally on the pushing wall 30 of the push button 29 which acts
as triggering means. As shown on FIG. 3, as a consequence of the safety
shield 8 having moved to its activation position, the push button 29 is
now allowed to move distally with respect to the housing 12 and the peg
31 of the push button 29 comes in abutment against the flexible tooth 18
of the inner cylinder 15, said flexible tooth 18 being thereby caused to
deflect radially outwardly. As a consequence, the radial stop 22 of the
piston rod 21 disengages from the proximal abutment surface 18a of the
flexible tooth 18 of the inner cylinder 15 and the second helical spring
34 is freed.

[0056] The second helical spring 34 tends to come back to its expanded
state and causes the distal movement of the piston rod 21. The piston rod
21 comes in abutment on the piston 7. The friction force of the piston 7
against the inner walls of the container 2 being higher than the force of
the second helical spring 34, the container 2 is also caused to move
distally under the effect of the expansion of the second helical spring
34.

[0057] As shown on FIG. 4, the distal movement of the container 2 causes
the insertion of the needle 6 in the injection site 4. At the same time,
and as a consequence of the same movement, the distal sloping surface 27
of the second ring 25 has come in abutment on the proximal sloping
surface 26b of the first ring 24, causing the flexible tooth 26 to
deflect inwardly radially and to disengage from the radial stop 14 of the
housing 12, as shown on FIG. 4. As a consequence, said first ring 24 is
freed from said housing 12. The first ring 24 is no more coupled to the
housing 12 in the distal direction. Moreover, in this insertion position,
the distal face 24b of the first ring 24 is in abutment against the
radial rim 9 of the safety shield 8: as a consequence, the first ring 24
is now coupled to the safety shield 8 in the proximal direction under the
biasing force of the first helical spring 33. The first helical spring 33
is now in a compressed state and the container 2 is thereby caused to be
stopped at a predetermined insertion depth. The second helical spring 34
in the example shown, acts as automatic injection means.

[0058] The force of the second helical spring 34 is therefore allowed to
overcome the friction force of the piston 7 against the inner walls of
the container 2 and the piston rod 21 is caused to push the piston 7
distally so as to realise the injection, as shown on FIG. 5.

[0059] At the end of injection, as shown on FIG. 5, the flexible tooth 26
of the first ring 24 is still disengaged from the radial stop 14 of the
housing 12. As a consequence, when the user withdraws the device 1 from
the injection site, the first helical spring 33, which is now coupled to
the safety shield 8 in the distal direction, is free to expand and deploy
the safety shield 8 over the needle 6 (step not shown); the safety shield
8 is therefore in its safety position, distally spaced from its rest
position, and in which it covers the needle 6 thereby preventing any
needle stick injury. The device of the invention is therefore
particularly safe.

[0060] As can be noticed from FIG. 4, the flexible tooth 26 is disengaged
from the radial stop 14 of the housing 12 as soon as the injection
starts. As a consequence, if the user inadvertently withdraws the device
1 of the invention from the injection site 4 before the end of the
injection, the safety shield 8 will automatically expand over the needle
6 and will prevent any needle stick injury.

[0061] The device of the invention provides for a very safe device, which
cannot be triggered as long as it is not correctly located at the
injection site and which does not hurt the user during the step of
deactivating the safety system. In particular, because of the presence of
specific isolating means, the user does not feel the force of the biasing
means intended to expand the safety shield at the end of injection.

[0062] The injection device of the invention also allows automatic
injection of a product to be performed by a patient without any risk of
needlestick injury, before, during and after use. In particular, the
safety shield of the device of the invention is in its active state right
at the end of the insertion step, before the injection step actually
begins. In this way, even if the patient decides to withdraw the device
before the end of the injection, then the safety shield automatically
extends over the needle.

Patent applications by Guillaume Grunhut, Grenoble FR

Patent applications by BECTON DICKINSON FRANCE

Patent applications in class Cover or protector for body entering conduit movable axially relative to one another

Patent applications in all subclasses Cover or protector for body entering conduit movable axially relative to one another